1. Field of the Invention
This invention relates to sealing means for a floating tank roof and a method of installing same, and more particularly to such a sealing means for covering the annular space between the floating roof and the tank while aiding in centering the roof on the liquid within the tank.
2. Description of the Prior Art
Heretofore, different sealing arrangements have been employed for covering the annular space between a floating roof and an associated cylindrical tank while aiding in centering the roof on the liquid within the tank. For example, U.S. Pat. No. 4,457,446 dated Jul. 3, 1984 shows a vertical cylindrical metal shoe adapted to slide vertically along the inner peripheral surface of the cylindrical tank with the shoe including a plurality of shoe segments or sections connected by vertically extending flexures. A flexible seal extends between the roof and the shoe to cover the annular space or clearance between the roof and the tank.
It has been common heretofore to connect such a metal shoe to a floating roof for vertical movement therewith. For example, U.S. Pat. No. 2,669,372 shows a floating roof with hangers secured between the floating roof and the shoe to effect vertical sliding movement of the shoe along the tank wall surface upon a corresponding vertical movement of the roof which may result from a change in the level of the liquid within the tank supporting the floating roof. Also, spring bands are provided between the floating roof and the shoe to force the shoe against the tank and the roof toward a centered position within the tank.
Other patents which show sealing means in an annular space between a floating roof and an associated tank include U.S. Pat. Nos. 1,665,163; 1,693,857; 1,900,904; and 4,162,022. However, the installation of sealing means heretofore positioned between a floating roof and a tank have been relatively complicated and time consuming, and many of such sealing means can not be installed while the tank is in service.